"Characterization of immune cells and inflammatory cytokines in the peritoneal fluid of patients with endometriosis" Endometriosis (EM) is an estrogen-dependent disease and one of the most common benign gynecological disorders of women in reproductive age. The appearance of functional endometrial tissue (stroma and endometrial glands) outside the uterine cavity, mostly as small peritoneal lesions, defines this chronic inflammatory disease. The pathomechanism remains unclear, thus there are no causal therapeutic methods established so far. It is known that different components of the immune system influence the pathogenesis of EM. Furthermore, studies have shown that besides endometriotic tissue, peritoneal fluid also generally contains immunocompetent cells. The aim of this study was to evaluate the potential role of immune cells and their inflammatory cytokines in the pathogenesis and establishment of EM. For this, flow cytometry, a Bio-PlexTM Cytokine Assay and an ELISA-Kit have been used. Different immune cell populations and 27 inflammatory cytokines, interleukins, and growth factors in the peritoneal fluid of EM patients and control patients (benign disorders like ovarian cysts or fibroids) have been detected and characterized. Additionally, the concentration of pro-inflammatory Neopterin, which is used as a biomarker in several chronic diseases, was analyzed. The results show that monocytes and macrophages are the dominating cells in the peritoneal fluid of women with EM and there is a positive correlation of cell size and severity of EM regarding this population. Additionally, their expression of HLA-DR is significantly lower. Furthermore, there are significantly higher levels of IL-1β, IL-1Ra, IL-2, IL-4, IL-8, IL-10, IL-12 (p70), IL-17α, FGFb, G-CSF, MCP-1, MIP-1α, TNF-α and Neopterin in the peritoneal fluid of affected patients. Especially the concentrations of IL-12 (p70), IL-17α and FGFb are significantly upregulated in mild EM, while IL-2, IL-8, MCP-1, TNF-α and MIP-1α show the highest levels in women with severe EM. These findings correlate with the assumption that altered immune cell activities influence the pathogenesis of EM by promoting chronic inflammation, vascularization, proliferation, and maintenance of endometriotic lesions. Lower expression of HLA-DR and varying cell size of monocytes and macrophages in women with EM show that there are qualitative alterations, and this population seems to play a crucial role in the pathogenesis of EM. The higher concentrations of pro- and anti-inflammatory cytokines indicate that both components of the immune response seem to take part in the complex pathomechanism of EM. Furthermore, it was the first time that Neopterin was analyzed as a potential new biomarker in this special and detailed context and this messenger has to be considered as a diagnostic parameter for EM in future studies.weiterlesen